"Steady-state" competence for bacterial transformation

1968 ◽  
Vol 14 (3) ◽  
pp. 290-292
Author(s):  
Herbert H. Eichhorn ◽  
Shigeyo Arikawa ◽  
Stephen Zamenhof
Keyword(s):  
Bacillus Subtilis ◽  
Steady State ◽  
Continuous Culture ◽  
Generation Time ◽  
Bacterial Transformation ◽  
Short Period ◽  
Minimal Media ◽  
Harmful Effects ◽  
Specific Phase

The cells of Bacillus subtilis, grown in minimal media, are known to become competent for transformation for a short period at a specific phase of ceil growth. In the present work the cells (strain 168 ind−) were grown in continuous culture (chemostat; glucose limiting, generation time 4 h, 37 °C). Aliquots were removed at 20- to 24-h intervals and immediately tested for competence. The viability (41 h) was 97%. The initial very low competence increased up to 200-fold within the 24 h and remained at this high, slowly decreasing level for at least 168 h. It is concluded that a long-lasting competence may develop and persist in the cells in continuous culture ("steady-state"), without demonstrable harmful effects to the population.

Metabolic flux analysis of hybridoma continuous culture steady state multiplicity

1999 ◽  
Vol 63 (6) ◽  
pp. 675-683 ◽  
Author(s):  
Brian D. Follstad ◽  
R. Robert Balcarcel ◽  
Gregory Stephanopoulos ◽  
Daniel I. C. Wang
Keyword(s):  
Steady State ◽  
Continuous Culture ◽  
Metabolic Flux Analysis ◽  
Metabolic Flux ◽  
Flux Analysis ◽  
State Multiplicity

scholarly journals Behavior of chlorella pyrenoidosa in steady state continuous culture

1970 ◽  
Author(s):  
Joseph N. Dabes ◽  
Charles R. Wilke ◽  
Kenneth H. Sauer
Keyword(s):  
Steady State ◽  
Continuous Culture ◽  
Chlorella Pyrenoidosa

Kinetic analysis of batch and continuous culture of Streptococcus cremoris HP

1978 ◽  
Vol 24 (4) ◽  
pp. 372-380 ◽  
Author(s):  
P. L. Rogers ◽  
L. Bramall ◽  
I. J. McDonald
Keyword(s):  
Lactic Acid ◽  
Steady State ◽  
Kinetic Analysis ◽  
Continuous Culture ◽  
Batch Culture ◽  
Lactic Acid Production ◽  
Streptococcus Cremoris ◽  
Lactose Utilization ◽  
State Growth ◽  
Batch Data

The growth of Streptococcus cremoris on a semidefined medium was studied at initial lactose concentrations of 0.2–5.0% in batch culture, and in lactose-limited chemostat cultures at 0.5% lactose. Kinetic analysis of the batch data, using statistical techniques, indicated the importance of lactose limitation and lactic acid inhibition of the growth of S. cremoris. A model for the biomass production, lactose utilization, and lactic acid production in batch culture was proposed. In continuous culture, it was found that steady state populations were maintained at higher dilution rates (D = 0.6–0.7 h−1) than the maximum predicted by batch culture (0.56 h−1). No evidence for a selection of fast-growing mutants was obtained. Copious growth adhering to the walls of the fermentor (i.e. wall growth) occurred very rapidly at higher dilution rates and this undoubtedly affected steady-state growth and wash-out and, as a consequence, the apparent maximum dilution rate.

STANDING‐WAVE PHENOMENA IN SHORT‐PERIOD SEISMIC NOISE

Geophysics ◽  
1965 ◽  
Vol 30 (6) ◽  
pp. 1179-1186 ◽  
Author(s):  
Indra N. Gupta
Keyword(s):  
Steady State ◽  
Standing Wave ◽  
Seismic Noise ◽  
P Wave ◽  
Stratified Medium ◽  
Alternative Theory ◽  
Compressional Waves ◽  
Short Period ◽  
Wave Phenomena ◽  
Phase Spectra

Short‐period vertical seismometers are used in deep holes at several sites to obtain the change with depth in amplitude and phase spectra of short‐period seismic noise. Although the observed spectra can be explained by an arbitrary combination of several Rayleigh modes, an alternative theory is suggested here. An attempt is made to explain both amplitude and phase spectra of observed microseisms of period less than 6 sec in terms of standing‐wave phenomena caused by steady‐state plane harmonic compressional waves propagating vertically through a horizontally stratified medium. At most sites, the observed data indicate satisfactory agreement with the expected results. A considerable fraction of the short‐period noise may, therefore, be regarded as P‐wave noise propagating vertically from below.

Monitoring biofilm detachment under dynamic changes in shear stress using laser-based particle size analysis and mass fractionation

2003 ◽  
Vol 47 (5) ◽  
pp. 69-76 ◽  
Author(s):  
Y.C. Choi ◽  
E. Morgenroth
Keyword(s):  
Shear Stress ◽  
Steady State ◽  
Rotational Speed ◽  
Dynamic Change ◽  
Size Analysis ◽  
Sudden Increase ◽  
Annular Reactor ◽  
Mass Fractionation ◽  
Short Period ◽  
Biofilm Detachment

Biofilm detachment under a dynamic change in shear stress was monitored using Focused Beam Reflectance Measurements (FBRM, LASENTEC®) and mass fractionation. An annular reactor was used to grow biofilm with glucose as substrate. Changing the rotational speed on the inner cylinder of the annular reactor from 150 RPM to 420 RPM induced a step increase in shear stress. It was observed that the rate of detachment increased rapidly after increasing shear stress and then returned to the previous level. Erosion was the dominant process of detachment under steady state operation, whereas sloughing was dominant following the sudden increase in shear stress. After reaching steady state detachment under high shear conditions, the rotational speed was decreased for a 12-hour period. During this brief period of lower shear, the biofilm adjusted to this new condition. When the shear stress was increased again, another sharp increase in effluent solids concentration was observed. A decrease in density indicates that the biofilm became more vulnerable to shear stress after being subjected to this short period of low shear.

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